Head Tracking w FlySky GT3B and Telemetry Dashboard for Gmade GOM 1/10 Rock Crawler

The project is divided into 3 parts:

1. Add head tracking (Channel 4-6) using Teensy 3.2 and toggle switching (Channel 7 & 8) functions in Flysky GT3B pistol transmitter 
2. Add front and back FPV camera into GOM
3. Add telemetry dashboard function using ST7735 and Arduino Nano

PART 1: Add head tracking function(Channel 4-6) using Teensy 3.2 and toggle switching (Channel 7 & 8) in Flysky GT3B pistol transmitter.
(Thank you for sharing by Dylan Fairbanks for instruction of adding head tracking function and additional channels using Teensy 3.2 and Flysky GT3B)

Pre-requisites: 

• Basic programming skill
• Basic soldering skill
• Understanding of PPM and PWM 

Components

• FlySky GT3B Transmitter and FS-R9B 8ch Receiver

• Teensy 3.2

 

• SkyZone 03O FPV Goggles (with Head Tracking Function)

• JR (Head Tracking) Cable(come with 03O FPV Goggles)

• 3.5mm Stereo Socket

• 2-ways Toggle Switch (3 Pins)
• 3-ways Toggle Switch (3 Pins)

• Axis Pan&Tilt Camera Mount

• 2 x Micro Servo 

Connection Diagram

Steps

1. First use of the Teensy 3.2 https://www.pjrc.com/teensy/first_use.html
2. Please read through “Basic Teensyduino Usage” if this is your first time to use Teensy https://www.pjrc.com/teensy/td_usage.html
3. Please cut USB Power at back of Teensy 3.2. https://www.pjrc.com/teensy/external_power.html

4. Unscrew and open the top cover of GT3B

5. Solder the wire (I am not a professional at soldering) 



6. Need cut original PPM Trace at the back of GT3 board 

7. Make the holes and install the 2 x toggle switch and 3.5MM audio socket

Programming

#include "PulsePosition.h"

#include <Servo.h> 
 
Servo myservo;
PulsePositionInput RadioIn(FALLING);
PulsePositionInput TrackerIn(FALLING);
PulsePositionOutput MixOut(FALLING);

const uint8_t  RADIO_INPUT_PIN   = 22; //input the transmitter signal
const uint8_t  TRACKER_INPUT_PIN = 21; //input the head tracker signal
const uint8_t  MIX_OUT_PIN       = 20; //output the mixed signal

void setup() {
  Serial.begin(9600);
  RadioIn.begin(RADIO_INPUT_PIN);
  TrackerIn.begin(TRACKER_INPUT_PIN);
  MixOut.begin(MIX_OUT_PIN);
  myservo.attach(7);  
  pinMode(5, INPUT_PULLUP); //for channel 8 two ways toggle switch - light switch 
  pinMode(6, INPUT_PULLUP); //for channel 7 three was toggle swich - high-lo-dig gear
  pinMode(7, INPUT_PULLUP); //for channel 7 three was toggle swich - high-lo-dig gear
}

void loop() {
  int i, num;
  int j = 0;
  
//read channel 1-3 signal from transmitter FlySky GT3B
num = RadioIn.available(); 
if (num > 0) {
  for (i=1; i<=3; i++) { 
   float val = RadioIn.read(i);
    MixOut.write(i, val);
  }
}
  
//read channel 5-7 signal from headtracker and map to 4,5,6. For setup of headtracking signal channel, please read the headtracker manual. 
//For example, Skyzone 03O google: https://files.banggood.com/2016/12/SKY03%20Manual-V1.0(1).pdf
//Skyzone 03O google manual : The PPM channels can be set in the menu: CH5-CH6, CH5-CH7, CH5-CH8, CH6-CH7, CH6-CH8 and CH7-CH8. 
num = TrackerIn.available();    
if (num > 0) {
   for (i=1; i <= num; i++) {
    float val = TrackerIn.read(i);
    switch (i) {
       case 5:
          j = 4;
         break;
       case 6:
          j = 5;
          break;
        case 7:
         j = 6;
          break;
        case 8:
       j = 0;
        break;
      default:
    break;
   }
   if (j != 0) {
        MixOut.write(j, val);
   }
  }
 }


if (digitalRead(7)==LOW) {
   MixOut.write(7, 900);              // tell Ch7 servo to go to Dig position (servo turns to left)
  } else 
   if (digitalRead(6)==LOW) {
   MixOut.write(7, 1950);             // tell Ch7 servo to go to High position (servo turns to right)
  } else 
   MixOut.write(7, 1500);             // tell Ch7 servo to go to Low position (servo no turns)

 if (digitalRead(5)==LOW) {
   MixOut.write(8, 1950);             // tell Ch8 servo(LED light control) to be off 
  } else 
   MixOut.write(8, 1500);     	      // tell Ch8 servo(LED light control) to be on
}

Ch4-6 - Head Tracking testing

Ch7 - 3-ways Hi-Lo-Dig Gear(Servo) testing

Ch8 - 2-ways Toggle Switch Testing

Ch 8 - Light Switch Testing (please refer to "Convert to a old servo to a light switch")

PART 2: Add front and back FPV camera into GOM

Components

• Rush Tank FPV Transmitter
• 2 x FPV camera
• FPV camera channel switch

Connection Diagram

Remark:
Make sure that the input voltage of CAM and FPV transmitter can be supported by battery voltage

PART 3: Add telemetry dashboard function using ST7735 and Arduino Nano

The Telemetry Dashboard

Please refer to "Display a customized image in ST7735" for display customized image" in this blog

Pre-requisites: 

• Basic of ST7735 and Arduino Nano
• https://www.electronics-lab.com/project/arduino-diy-photo-frame/
• https://learn.adafruit.com/1-8-tft-display?view=all
• Basic soldering skill
• Understanding of PPM and PWM 

Components

ST7735 1.8" TFT LCD

Arduino Nano

Connection Diagram

Programming

#include <SPI.h>

#include <Adafruit_GFX.h>

#include <Adafruit_ST7735.h> // include Hardware library

#define TFT_CS   10

#define TFT_RST  9  

#define TFT_DC   8

#define TFT_SCLK 13   

#define TFT_MOSI 11   

Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS,  TFT_DC, TFT_RST);

#define BACKCOLOR 0x18E3

#define BARCOLOR 0x0620

#define SCALECOLOR 0xFFFF

#define BLACK   0x0000

#define BLUE    0xF800

#define PURPLE  0xF81F

#define CYAN    0xFFE0  

#define WHITE   0xFFFF

#define GRAY    0x8410

#define RED     0xF800

#define ORANGE  0xFA60

#define YELLOW  0xFFE0

#define LIME    0x07FF

#define GREEN   0x07E0

#define AQUA    0x04FF

#define MAGENTA 0xF81F

#define PINK    0xF8FF

const int analogIn = A0;

int RawValue = 0;

int LastPercent = 0;

double throttle;

int gear;

int val=0;

int preval=0;

int FNB=0;

int preFNB=0;

int meter=0;

int premeter=0;

int gearval=0;

int pregearval=0;

// Bear Logo

const unsigned char bearlogo [] PROGMEM = {

  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 

  0x00, 0x00, 0x00, 0x00, 0x01, 0xfc, 0x00, 0x00, 0x00, 0x00, 0x07, 0xff, 0x00, 0x00, 0x00, 0x00, 

  0x1f, 0x3f, 0x80, 0x00, 0x00, 0x00, 0x7c, 0x07, 0xc0, 0x00, 0x00, 0x03, 0xf0, 0x01, 0xf0, 0x00, 

  0x00, 0x0f, 0xe0, 0x31, 0xf8, 0x00, 0x00, 0x1f, 0xe1, 0xff, 0xfc, 0x00, 0x00, 0x7f, 0xff, 0x0f, 

  0xfe, 0x00, 0x00, 0xfe, 0x00, 0x01, 0xff, 0x00, 0x01, 0xfe, 0x00, 0x00, 0x3f, 0x80, 0x03, 0xf6, 

  0x00, 0x00, 0x1f, 0xc0, 0x07, 0xef, 0x00, 0x00, 0x1f, 0xe0, 0x0f, 0x9b, 0x00, 0x00, 0x1f, 0xe0, 

  0x0f, 0xb2, 0x00, 0x00, 0x3f, 0xe0, 0x0f, 0xe4, 0x00, 0x00, 0x3d, 0xf0, 0x1f, 0x64, 0x00, 0x00, 

  0x3d, 0xf0, 0x1f, 0x40, 0x00, 0x00, 0x1c, 0xf0, 0x1f, 0xc0, 0x00, 0xc0, 0x3e, 0xf0, 0x1f, 0x40, 

  0x00, 0xe0, 0x30, 0xf0, 0x1f, 0x60, 0x01, 0xe0, 0x61, 0xf8, 0x1f, 0x60, 0x01, 0xf0, 0xc1, 0xf8, 

  0x1f, 0x60, 0x00, 0x18, 0x01, 0xf0, 0x1d, 0xc0, 0x00, 0x18, 0x01, 0xf0, 0x1d, 0x80, 0x00, 0x10, 

  0x01, 0xf0, 0x1d, 0x80, 0x00, 0x00, 0x01, 0xf0, 0x0c, 0x00, 0x00, 0x00, 0x01, 0xf0, 0x0f, 0x10, 

  0x00, 0x00, 0x01, 0xf0, 0x1f, 0x20, 0x00, 0x00, 0x03, 0xe0, 0x1f, 0x60, 0x00, 0x00, 0x03, 0xe0, 

  0x1f, 0xe0, 0x00, 0x00, 0x03, 0xc0, 0x1f, 0xc0, 0x00, 0x00, 0x03, 0x80, 0x3f, 0xc0, 0x00, 0x00, 

  0x03, 0x80, 0x3f, 0xe0, 0x00, 0x00, 0x07, 0x00, 0x3f, 0xe0, 0x1f, 0x80, 0x06, 0x00, 0x1f, 0xf8, 

  0x1f, 0x00, 0x06, 0x00, 0x0f, 0xfc, 0x1e, 0x00, 0x0c, 0x00, 0x07, 0xfc, 0x06, 0x00, 0x0c, 0x00, 

  0x07, 0xf8, 0x02, 0x00, 0x08, 0x00, 0x3f, 0xf0, 0x00, 0x00, 0x18, 0x00, 0x0f, 0xf0, 0x00, 0x00, 

  0x10, 0x00, 0x0f, 0xf8, 0x02, 0x00, 0x30, 0x00, 0x0f, 0xf8, 0x00, 0x00, 0x30, 0x00, 0x07, 0xfc, 

  0x06, 0x00, 0x70, 0x00, 0x00, 0x7e, 0x0c, 0x00, 0x70, 0x00, 0x00, 0x7e, 0xf0, 0x01, 0xf0, 0x00, 

  0x00, 0x01, 0xff, 0xff, 0xf0, 0x00, 0x00, 0x00, 0x7f, 0xff, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 

  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 

  0x00, 0x00, 0x00, 0x00

};

// gomlogo, 47x18px

const unsigned char gomlogo [] PROGMEM = {

   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1f, 0xf0, 0x3f, 0xe1, 0xe0, 0x78, 0x3f, 0xf8, 0x7f, 0xf1, 

  0xf0, 0xf8, 0x7f, 0xfc, 0xff, 0xf9, 0xf0, 0xf8, 0x7c, 0x7c, 0xf8, 0xf9, 0xf9, 0xf8, 0x78, 0x00, 

  0xf0, 0x79, 0xff, 0xf8, 0x78, 0xfc, 0xf0, 0x79, 0xff, 0xf8, 0x78, 0x7c, 0xf0, 0x79, 0xff, 0xf8, 

  0x78, 0x7c, 0xf0, 0x79, 0xef, 0x78, 0x7f, 0xfc, 0xff, 0xf9, 0xe6, 0x78, 0x3f, 0xfc, 0x7f, 0xf1, 

  0xe0, 0x78, 0x1f, 0xec, 0x3f, 0xe1, 0xc0, 0x38, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x29, 0xce, 

  0xa1, 0xd2, 0xe7, 0x48, 0x2f, 0x5a, 0xe3, 0xfa, 0xc4, 0x38, 0x3f, 0x58, 0xe3, 0xda, 0xf7, 0xb0, 

  0x2f, 0xde, 0xb3, 0xfe, 0xf7, 0xb0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00

};

void setup() {

 Serial.begin(9600);

 pinMode(6, INPUT); //get throttle signal from ch2

 pinMode(4, INPUT); //get hi-lo-dig signal from ch7

 tft.initR(INITR_BLACKTAB);

 tft.fillScreen(BACKCOLOR); // back colour in background of ST7735

 tft.setRotation(1); //set as landscape orientation

 //display header in dashboard

 tft.setTextColor(WHITE);

 tft.setCursor(10,11);

 tft.setTextSize(1);

 tft.println("GOM TELEMETRY DASHBOARD");

 //draw marker of acceleration bar

 tft.drawLine(5,40,150,40,GRAY);

 tft.setTextColor(WHITE);

 tft.setCursor(5,45);

 tft.println("1");

 tft.setCursor(25,45);

 tft.println("2");

 tft.setCursor(45,45);

 tft.println("3");

 tft.setCursor(65,45);

 tft.println("4");

 tft.setCursor(85,45);

 tft.println("5");

 tft.setCursor(105,45);

 tft.println("6");

 tft.setCursor(125,45);

 tft.println("7");

 tft.setCursor(145,45);

 tft.println("8");

 //Print "0" as acceleration meter as default

 tft.setTextColor(WHITE);

 tft.setCursor(45,62);

 tft.setTextSize(4);

 tft.println("0");

 //Print "N" as default

 tft.setTextColor(WHITE);

 tft.setCursor(15,66);

 tft.setTextSize(3);

 tft.println("N");

 //display hi-lo-dig gear 

 tft.fillCircle(20,116,5,GRAY);

 tft.fillCircle(50,116,5,GREEN);

 tft.fillCircle(80,116,5,GRAY);

 tft.drawLine(25,116,45,116,WHITE);

 tft.drawLine(55,116,75,116,WHITE);

 tft.setTextColor(WHITE);

 tft.setCursor(16,103);

 tft.setTextSize(1);

 tft.println("HI");

 tft.setTextColor(WHITE);

 tft.setCursor(46,103);

 tft.setTextSize(1);

 tft.println("LO");

 tft.setTextColor(WHITE);

 tft.setCursor(73,103);

 tft.setTextSize(1);

 tft.println("DIG");

 tft.drawBitmap(110, 55, bearlogo, 47, 54, WHITE); //draw bear logo

 tft.drawBitmap(110, 107, gomlogo, 47, 18, WHITE); //draw gom logo

}

void loop(){  

 int newPercent;

 int i;

 int j=1;

 int k=1;

 int colour;

 int diff;

 int FNBdiff;

 //get signal from pin6 (Ch2)

 throttle = pulseIn(6, HIGH);

 if (throttle>=1514) //car moving backward

  FNB = -1;

  else if (throttle<1479) //car moving forward

  FNB = 1;

  else //car in neutral

  FNB = 0;

 if (throttle<1479){ //if moving forward, val is for acceleration bar 

  val = map(throttle, 1479, 989,0,7);

  meter = map(throttle, 1479, 989, 0, 99); //map the throttle signal to 0-99, meter is for acceleration meter

 }

 else { 

  val=0;

  meter=0;

 }

 diff= val - preval; //calculate the different value for acceleration bar 

 if (diff>0) //acceleration, draw the colour bar

 {

  j=preval*20;

  for (i=preval; i<=val ; i++){

   if (i>=5) 

    else colour = RED;

   if (i>=3)

    else colour = YELLOW;

   colour = GREEN;

   Tft.fillRect(j+4, 27, 20, 10, colour);

   j=j+20;

  }

 }

 else if (diff <0) //deceleration, draw "black" bar

 {

  j=preval*20;

  for (i=preval; i>=val ; i--){

  tft.fillRect(j+4, 27, 20, 10, BLACK);

  j=j-20;

  }

 }

 preval=val;

 //display "D" - Forward, "N" - Neutral, "R" - Backward

 tft.setTextColor(PURPLE);

 tft.setCursor(15,66);

 tft.setTextSize(3);

 if ((FNB-preFNB)!=0) {

   if(FNB>0){

      tft.setTextColor(GREEN);

      tft.fillRect(15, 66, 20, 23, BLACK);

      tft.println("D");

      }

      else

      if (FNB<0){

        tft.setTextColor(RED);

        tft.fillRect(15, 66, 20, 23, BLACK);

        tft.println("R");

      }

      else {

        tft.setTextColor(WHITE);

        tft.fillRect(15, 66, 20, 23, BLACK);

        tft.println("N");

      }

 }

    

 //display acceleration meter

 if ((FNB-preFNB)!=0){ //display "0" if deceleration

   tft.fillRect(45, 62, 60, 30, BLACK);

   tft.setTextColor(WHITE);

   tft.setCursor(45,62);

   tft.setTextSize(4);

   tft.println("0");

 } 

 else

 if (FNB>0){ //display "meter" if acceleration

   if((meter-premeter)>1){

     tft.fillRect(45, 62, 60, 30, BLACK);

     tft.setTextColor(WHITE);

     tft.setCursor(45,62);

     tft.setTextSize(4);

     tft.println(meter);

   }

 }

 premeter=meter;

 preFNB=FNB;  

 //display Hi-lo-Dig Gear

 gear = pulseIn(4, HIGH);

 if (gear<950){ //display Hi Gear

   gearval=1;

   if ((gearval-pregearval)!=0){

     tft.fillCircle(20,116,5,GREEN);

     tft.fillCircle(50,116,5,GRAY);

     tft.fillCircle(80,116,5,GRAY);

   }

 }

 else

 if (gear>1900) { //display Dig Gear

   gearval=-1;

   if ((gearval-pregearval)!=0){

     tft.fillCircle(20,116,5,GRAY);

     tft.fillCircle(50,116,5,GRAY);

     tft.fillCircle(80,116,5,GREEN);

   }

 }

 else{

  gearval=0;

  if ((gearval-pregearval)!=0){ //display Lo Gear

    tft.fillCircle(20,116,5,GRAY);

    tft.fillCircle(50,116,5,GREEN);

    tft.fillCircle(80,116,5,GRAY);

  }

 }

 pregearval=gearval;

}

Dashboard - Throttle testing

Dashboard - Hi-Lo-Dig Gear testing